Modern wireless data communication systems provide bandwidth for use by rich computing applications on mobile devices. For example, users of wireless devices such as smart phones can make telephone calls, receive emails, and even receive full-motion audio/video broadcasts on their mobile devices. Every time a great new service is offered, users of wireless devices consume data associated with the service, requiring more and more bandwidth. As a result, the airwaves are filled with data going to and from an increasing number of wireless computing devices that each require growing amounts of data.
A data packet transmitted in a wireless communication system may not always be received by a designated recipient computing device. Interfering signals from other computing devices or from natural phenomena may overpower the portion of the signal that includes the data packet so that the entire data packet, or portions thereof, are unintelligible to the receiving device or include errors. Similarly, the transmitting device or the receiving device may move behind an obstruction, so that communication signals between the devices are inhibited for a temporary period of time.
The electromagnetic spectrum that wireless devices use for wireless communication is treated as a precious resource. Governments control where in the spectrum particular wireless technologies can operate, and also control who can use particular portions of the spectrum (e.g., through high-cost spectrum auctions). Thus, various mechanisms are used to maximize the data that a network of wireless devices and corresponding base stations can exchange in a particular portion of spectrum. Interfering signals may provide fewer errors at reduced data rates than at higher data rates. Accordingly, a communication system may transmit at higher data rates when less interference is detected, and at lower data rates when more interference is detected.